Merge pull request #460 from s-Joshua-s/fix/proxy-probe-fallback

fix(proxy): 增加代理探测的多 URL 回退机制

backend/internal/repository/proxy_probe_service.go

@@ -28,7 +28,6 @@ func NewProxyExitInfoProber(cfg *config.Config) service.ProxyExitInfoProber {
 		log.Printf("[ProxyProbe] Warning: insecure_skip_verify is not allowed and will cause probe failure.")
 	}
 	return &proxyProbeService{
-		ipInfoURL:          defaultIPInfoURL,
 		insecureSkipVerify: insecure,
 		allowPrivateHosts:  allowPrivate,
 		validateResolvedIP: validateResolvedIP,
@@ -36,12 +35,20 @@ func NewProxyExitInfoProber(cfg *config.Config) service.ProxyExitInfoProber {
 }
 
 const (
-	defaultIPInfoURL         = "http://ip-api.com/json/?lang=zh-CN"
 	defaultProxyProbeTimeout = 30 * time.Second
 )
 
+// probeURLs 按优先级排列的探测 URL 列表
+// 某些 AI API 专用代理只允许访问特定域名，因此需要多个备选
+var probeURLs = []struct {
+	url    string
+	parser string // "ip-api" or "httpbin"
+}{
+	{"http://ip-api.com/json/?lang=zh-CN", "ip-api"},
+	{"http://httpbin.org/ip", "httpbin"},
+}
+
 type proxyProbeService struct {
-	ipInfoURL          string
 	insecureSkipVerify bool
 	allowPrivateHosts  bool
 	validateResolvedIP bool
@@ -60,8 +67,21 @@ func (s *proxyProbeService) ProbeProxy(ctx context.Context, proxyURL string) (*s
 		return nil, 0, fmt.Errorf("failed to create proxy client: %w", err)
 	}
 
+	var lastErr error
+	for _, probe := range probeURLs {
+		exitInfo, latencyMs, err := s.probeWithURL(ctx, client, probe.url, probe.parser)
+		if err == nil {
+			return exitInfo, latencyMs, nil
+		}
+		lastErr = err
+	}
+
+	return nil, 0, fmt.Errorf("all probe URLs failed, last error: %w", lastErr)
+}
+
+func (s *proxyProbeService) probeWithURL(ctx context.Context, client *http.Client, url string, parser string) (*service.ProxyExitInfo, int64, error) {
 	startTime := time.Now()
-	req, err := http.NewRequestWithContext(ctx, "GET", s.ipInfoURL, nil)
+	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
 	if err != nil {
 		return nil, 0, fmt.Errorf("failed to create request: %w", err)
 	}
@@ -78,6 +98,22 @@ func (s *proxyProbeService) ProbeProxy(ctx context.Context, proxyURL string) (*s
 		return nil, latencyMs, fmt.Errorf("request failed with status: %d", resp.StatusCode)
 	}
 
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, latencyMs, fmt.Errorf("failed to read response: %w", err)
+	}
+
+	switch parser {
+	case "ip-api":
+		return s.parseIPAPI(body, latencyMs)
+	case "httpbin":
+		return s.parseHTTPBin(body, latencyMs)
+	default:
+		return nil, latencyMs, fmt.Errorf("unknown parser: %s", parser)
+	}
+}
+
+func (s *proxyProbeService) parseIPAPI(body []byte, latencyMs int64) (*service.ProxyExitInfo, int64, error) {
 	var ipInfo struct {
 		Status      string `json:"status"`
 		Message     string `json:"message"`
@@ -89,13 +125,12 @@ func (s *proxyProbeService) ProbeProxy(ctx context.Context, proxyURL string) (*s
 		CountryCode string `json:"countryCode"`
 	}
 
-	body, err := io.ReadAll(resp.Body)
-	if err != nil {
-		return nil, latencyMs, fmt.Errorf("failed to read response: %w", err)
-	}
-
 	if err := json.Unmarshal(body, &ipInfo); err != nil {
-		return nil, latencyMs, fmt.Errorf("failed to parse response: %w", err)
+		preview := string(body)
+		if len(preview) > 200 {
+			preview = preview[:200] + "..."
+		}
+		return nil, latencyMs, fmt.Errorf("failed to parse response: %w (body: %s)", err, preview)
 	}
 	if strings.ToLower(ipInfo.Status) != "success" {
 		if ipInfo.Message == "" {
@@ -116,3 +151,19 @@ func (s *proxyProbeService) ProbeProxy(ctx context.Context, proxyURL string) (*s
 		CountryCode: ipInfo.CountryCode,
 	}, latencyMs, nil
 }
+
+func (s *proxyProbeService) parseHTTPBin(body []byte, latencyMs int64) (*service.ProxyExitInfo, int64, error) {
+	// httpbin.org/ip 返回格式: {"origin": "1.2.3.4"}
+	var result struct {
+		Origin string `json:"origin"`
+	}
+	if err := json.Unmarshal(body, &result); err != nil {
+		return nil, latencyMs, fmt.Errorf("failed to parse httpbin response: %w", err)
+	}
+	if result.Origin == "" {
+		return nil, latencyMs, fmt.Errorf("httpbin: no IP found in response")
+	}
+	return &service.ProxyExitInfo{
+		IP: result.Origin,
+	}, latencyMs, nil
+}

backend/internal/repository/proxy_probe_service_test.go

@@ -5,6 +5,7 @@ import (
 	"io"
 	"net/http"
 	"net/http/httptest"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -21,7 +22,6 @@ type ProxyProbeServiceSuite struct {
 func (s *ProxyProbeServiceSuite) SetupTest() {
 	s.ctx = context.Background()
 	s.prober = &proxyProbeService{
-		ipInfoURL:         "http://ip-api.test/json/?lang=zh-CN",
 		allowPrivateHosts: true,
 	}
 }
@@ -49,12 +49,16 @@ func (s *ProxyProbeServiceSuite) TestProbeProxy_UnsupportedProxyScheme() {
 	require.ErrorContains(s.T(), err, "failed to create proxy client")
 }
 
-func (s *ProxyProbeServiceSuite) TestProbeProxy_Success() {
-	seen := make(chan string, 1)
+func (s *ProxyProbeServiceSuite) TestProbeProxy_Success_IPAPI() {
 	s.setupProxyServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		seen <- r.RequestURI
+		// 检查是否是 ip-api 请求
+		if strings.Contains(r.RequestURI, "ip-api.com") {
 			w.Header().Set("Content-Type", "application/json")
 			_, _ = io.WriteString(w, `{"status":"success","query":"1.2.3.4","city":"c","regionName":"r","country":"cc","countryCode":"CC"}`)
+			return
+		}
+		// 其他请求返回错误
+		w.WriteHeader(http.StatusServiceUnavailable)
 	}))
 
 	info, latencyMs, err := s.prober.ProbeProxy(s.ctx, s.proxySrv.URL)
@@ -65,45 +69,59 @@ func (s *ProxyProbeServiceSuite) TestProbeProxy_Success() {
 	require.Equal(s.T(), "r", info.Region)
 	require.Equal(s.T(), "cc", info.Country)
 	require.Equal(s.T(), "CC", info.CountryCode)
+}
 
-	// Verify proxy received the request
-	select {
-	case uri := <-seen:
-		require.Contains(s.T(), uri, "ip-api.test", "expected request to go through proxy")
-	default:
-		require.Fail(s.T(), "expected proxy to receive request")
+func (s *ProxyProbeServiceSuite) TestProbeProxy_Success_HTTPBinFallback() {
+	s.setupProxyServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// ip-api 失败
+		if strings.Contains(r.RequestURI, "ip-api.com") {
+			w.WriteHeader(http.StatusServiceUnavailable)
+			return
 		}
+		// httpbin 成功
+		if strings.Contains(r.RequestURI, "httpbin.org") {
+			w.Header().Set("Content-Type", "application/json")
+			_, _ = io.WriteString(w, `{"origin": "5.6.7.8"}`)
+			return
+		}
+		w.WriteHeader(http.StatusServiceUnavailable)
+	}))
+
+	info, latencyMs, err := s.prober.ProbeProxy(s.ctx, s.proxySrv.URL)
+	require.NoError(s.T(), err, "ProbeProxy should fallback to httpbin")
+	require.GreaterOrEqual(s.T(), latencyMs, int64(0), "unexpected latency")
+	require.Equal(s.T(), "5.6.7.8", info.IP)
 }
 
-func (s *ProxyProbeServiceSuite) TestProbeProxy_NonOKStatus() {
+func (s *ProxyProbeServiceSuite) TestProbeProxy_AllFailed() {
 	s.setupProxyServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(http.StatusServiceUnavailable)
 	}))
 
 	_, _, err := s.prober.ProbeProxy(s.ctx, s.proxySrv.URL)
 	require.Error(s.T(), err)
-	require.ErrorContains(s.T(), err, "status: 503")
+	require.ErrorContains(s.T(), err, "all probe URLs failed")
 }
 
 func (s *ProxyProbeServiceSuite) TestProbeProxy_InvalidJSON() {
 	s.setupProxyServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if strings.Contains(r.RequestURI, "ip-api.com") {
+			w.Header().Set("Content-Type", "application/json")
+			_, _ = io.WriteString(w, "not-json")
+			return
+		}
+		// httpbin 也返回无效响应
+		if strings.Contains(r.RequestURI, "httpbin.org") {
 			w.Header().Set("Content-Type", "application/json")
 			_, _ = io.WriteString(w, "not-json")
+			return
+		}
+		w.WriteHeader(http.StatusServiceUnavailable)
 	}))
 
 	_, _, err := s.prober.ProbeProxy(s.ctx, s.proxySrv.URL)
 	require.Error(s.T(), err)
-	require.ErrorContains(s.T(), err, "failed to parse response")
-}
-
-func (s *ProxyProbeServiceSuite) TestProbeProxy_InvalidIPInfoURL() {
-	s.prober.ipInfoURL = "://invalid-url"
-	s.setupProxyServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		w.WriteHeader(http.StatusOK)
-	}))
-
-	_, _, err := s.prober.ProbeProxy(s.ctx, s.proxySrv.URL)
-	require.Error(s.T(), err, "expected error for invalid ipInfoURL")
+	require.ErrorContains(s.T(), err, "all probe URLs failed")
 }
 
 func (s *ProxyProbeServiceSuite) TestProbeProxy_ProxyServerClosed() {
@@ -114,6 +132,40 @@ func (s *ProxyProbeServiceSuite) TestProbeProxy_ProxyServerClosed() {
 	require.Error(s.T(), err, "expected error when proxy server is closed")
 }
 
+func (s *ProxyProbeServiceSuite) TestParseIPAPI_Success() {
+	body := []byte(`{"status":"success","query":"1.2.3.4","city":"Beijing","regionName":"Beijing","country":"China","countryCode":"CN"}`)
+	info, latencyMs, err := s.prober.parseIPAPI(body, 100)
+	require.NoError(s.T(), err)
+	require.Equal(s.T(), int64(100), latencyMs)
+	require.Equal(s.T(), "1.2.3.4", info.IP)
+	require.Equal(s.T(), "Beijing", info.City)
+	require.Equal(s.T(), "Beijing", info.Region)
+	require.Equal(s.T(), "China", info.Country)
+	require.Equal(s.T(), "CN", info.CountryCode)
+}
+
+func (s *ProxyProbeServiceSuite) TestParseIPAPI_Failure() {
+	body := []byte(`{"status":"fail","message":"rate limited"}`)
+	_, _, err := s.prober.parseIPAPI(body, 100)
+	require.Error(s.T(), err)
+	require.ErrorContains(s.T(), err, "rate limited")
+}
+
+func (s *ProxyProbeServiceSuite) TestParseHTTPBin_Success() {
+	body := []byte(`{"origin": "9.8.7.6"}`)
+	info, latencyMs, err := s.prober.parseHTTPBin(body, 50)
+	require.NoError(s.T(), err)
+	require.Equal(s.T(), int64(50), latencyMs)
+	require.Equal(s.T(), "9.8.7.6", info.IP)
+}
+
+func (s *ProxyProbeServiceSuite) TestParseHTTPBin_NoIP() {
+	body := []byte(`{"origin": ""}`)
+	_, _, err := s.prober.parseHTTPBin(body, 50)
+	require.Error(s.T(), err)
+	require.ErrorContains(s.T(), err, "no IP found")
+}
+
 func TestProxyProbeServiceSuite(t *testing.T) {
 	suite.Run(t, new(ProxyProbeServiceSuite))
 }